• 제목/요약/키워드: 3D Fluid Simulation

Search Result 319, Processing Time 0.027 seconds

Numerical Simulation of Three Dimensional Free Surface Flow (3차원 자유표면 유동의 수치 시뮬레이션)

  • 강신영
    • Journal of Ocean Engineering and Technology
    • /
    • v.4 no.1
    • /
    • pp.55-61
    • /
    • 1990
  • For the tracking of three dimensional free surface motions, a method referred to as the Volume of Fluid(VOF) algorithm is extended. In order to calculate the slope of three dimensional free surface which is the most important for the advection algorithm that decides the amount of fluid from cell to cell and for the application of free surface boundary condition, a simple method utilizing two dimensional slope informations is introduced. The extended algroithm is tested by demonstrating the simulation of a propagating sinusoidal wave through the channel whose width changes abruptly.

  • PDF

Resistance Performance Simulation of Simple Ship Hull Using Graph Neural Network (그래프 신경망을 이용한 단순 선박 선형의 저항성능 시뮬레이션)

  • TaeWon, Park;Inseob, Kim;Hoon, Lee;Dong-Woo, Park
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.59 no.6
    • /
    • pp.393-399
    • /
    • 2022
  • During the ship hull design process, resistance performance estimation is generally calculated by simulation using computational fluid dynamics. Since such hull resistance performance simulation requires a lot of time and computation resources, the time taken for simulation is reduced by CPU clusters having more than tens of cores in order to complete the hull design within the required deadline of the ship owner. In this paper, we propose a method for estimating resistance performance of ship hull by simulation using a graph neural network. This method converts the 3D geometric information of the hull mesh and the physical quantity of the surface into a mathematical graph, and is implemented as a deep learning model that predicts the future simulation state from the input state. The method proposed in the resistance performance experiment of simple hull showed an average error of about 3.5 % throughout the simulation.

Investigation to Metal 3D Printing Additive Manufacturing (AM) Process Simulation Technology (II) (금속 3D 프린팅 적층제조(AM) 공정 시뮬레이션 기술에 관한 고찰(II))

  • Kim, Yong Seok;Choi, Seong Woong;Yang, Soon Yong
    • Journal of Drive and Control
    • /
    • v.16 no.3
    • /
    • pp.51-58
    • /
    • 2019
  • The objective of this study was to investigate a simulation technology for the AM field based on ANSYS Inc.. The introduction of metal 3D printing AM process, and the examining of the present status of AM process simulation software, and the AM process simulation processor were done in the previous study (part 1). This present study (part 2) examined the use of the AM process simulation processor, presented in Part 1, through direct execution of Topology Optimization, Ansys Workbench, Additive Print and Additive Science. Topology Optimization can optimize additive geometry to reduce mass while maintaining strength for AM products. This can reduce the amount of material required for additive and significantly reduce additive build time. Ansys Workbench and Additive Print simulate the build process in the AM process and optimize various process variables (printing parameters and supporter composition), which will enable the AM to predict the problems that may occur during the build process, and can also be used to predict and correct deformations in geometry. Additive Science can simulate the material to find the material characteristic before the AM process simulation or build-up. This can be done by combining specimen preparation, measurement, and simulation for material measurements to find the exact material characteristics. This study will enable the understanding of the general process of AM simulation more easily. Furthermore, it will be of great help to a reader who wants to experience and appreciate AM simulation for the first time.

Quad Tree Based 2D Smoke Super-resolution with CNN (CNN을 이용한 Quad Tree 기반 2D Smoke Super-resolution)

  • Hong, Byeongsun;Park, Jihyeok;Choi, Myungjin;Kim, Changhun
    • Journal of the Korea Computer Graphics Society
    • /
    • v.25 no.3
    • /
    • pp.105-113
    • /
    • 2019
  • Physically-based fluid simulation takes a lot of time for high resolution. To solve this problem, there are studies that make up the limitation of low resolution fluid simulation by using deep running. Among them, Super-resolution, which converts low-resolution simulation data to high resolution is under way. However, traditional techniques require to the entire space where there are no density data, so there are problems that are inefficient in terms of the full simulation speed and that cannot be computed with the lack of GPU memory as input resolution increases. In this paper, we propose a new method that divides and classifies 2D smoke simulation data into the space using the quad tree, one of the spatial partitioning methods, and performs Super-resolution only required space. This technique accelerates the simulation speed by computing only necessary space. It also processes the divided input data, which can solve GPU memory problems.

Comparison of the fluid simulation with experimental data of excited Xe species density in PDP cell

  • Yang, Sung-Soo;Ko, Sang-Woo;Kim, Hyun-Chul;Mukherjee, Sudeshna;Lee, Jae-Koo
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 2003.07a
    • /
    • pp.739-742
    • /
    • 2003
  • We have compared 2-D and 3-D fluid simulation results of alternating current plasma display panel (AC-PDP) cell with experimentally measured two kinds of excited Xe species $Xe^{\ast}(^{3}P_{1})$ and $Xe^{\ast}(^{3}P_{2})$ characteristics. Although direct experimental access and diagnostics of the discharge in a PDP cell is problematic due to the small cell size, some of experimental technologies have made it possible to diagnose the behavior of excited Xe species [1, 2]. The simulation shows the similar characteristics to the experimental results in the excited Xe species density distribution and the number of excited Xe atoms in anode and cathode region. In certain cases, we obtained the arch-shaped discharge path between two sustain electrodes due to the additional pulse applied to address electrode analogous to experiment. This long path discharge induced higher luminous and discharge efficiency compared to the standard case.

  • PDF

A Study of Performance Estimate and Flow Analysis of the 500 kW Horizontal-Axis Wind Turbine by CFD (CFD에 의한 500kW급 수평축 풍력발전용 터빈의 성능평가 및 유동해석에 관한 연구)

  • Kim, Y.T.;Kim, B.S.;Kim, J.H.;Nam, C.D.;Lee, Y.H.
    • The KSFM Journal of Fluid Machinery
    • /
    • v.5 no.4 s.17
    • /
    • pp.32-39
    • /
    • 2002
  • The purpose of this 3-D numerical simulation is to calculate and examine the complex 3-D stall phenomena on the rotor blade and wake distribution of the wind turbine. The flow characteristics of 500kW Horizontal Axis Wind Turbine (HAWT) are compared with the calculated 3-D stall phenomena and wake distribution. We used the CFX-TASCflow to predict flow and power characteristics of the wind turbine. The CFD results are somewhat consistent with the BEM (Blade Element Momentum) results. And, the rotational speed becomes faster, the 3-D stall region becomes smaller. Moreover, the pressure distribution on the pressure side that directly gets the incoming wind grows high as it goes toward the tip of the blade. The pressure distribution on the blade's suction side tells us that the pressure becomes low in the leading edge of the airfoil as it moves from the hub to the tip. However, we are not able to precisely predict on the power coefficient of the rotor blade at the position of generating complex 3-D stall region.

Numerical simulation and experimental study of non-stationary downburst outflow based on wall jet model

  • Yongli Zhong;Yichen Liu;Hua Zhang;Zhitao Yan;Xinpeng Liu;Jun Luo;Kaihong Bai;Feng Li
    • Wind and Structures
    • /
    • v.38 no.2
    • /
    • pp.129-146
    • /
    • 2024
  • Aiming at the problem of non-stationary wind field simulation of downbursts, a non-stationary down-burst generation system was designed by adding a nozzle and program control valve to the inlet of the original wall jet model. The computational fluid dynamics (CFD) method was used to simulate the downburst. Firstly, the two-dimensional (2D) model was used to study the outflow situation, and the database of working conditions was formed. Then the combined superposition of working conditions was carried out to simulate the full-scale measured downburst. The three-dimensional (3D) large eddy simulation (LES) was used for further verification based on this superposition condition. Finally, the wind tunnel test is used to further verify. The results show that after the valve is opened, the wind ve-locity at low altitude increases rapidly, then stays stable, and the wind velocity at each point fluctuates. The velocity of the 2D model matches the wind velocity trend of the measured downburst well. The 3D model matches the measured downburst flow in terms of wind velocity and pulsation characteris-tics. The time-varying mean wind velocity of the wind tunnel test is in better agreement with the meas-ured time-varying mean wind velocity of the downburst. The power spectrum of fluctuating wind ve-locity at different vertical heights for the test condition also agrees well with the von Karman spectrum, and conforms to the "-5/3" law. The vertical profile of the maximum time-varying average wind veloci-ty obtained from the test shows the basic characteristics of the typical wind profile of the downburst. The effectiveness of the downburst generation system is verified.

Simulating three dimensional wave run-up over breakwaters covered by antifer units

  • Najafi-Jilani, A.;Niri, M. Zakiri;Naderi, Nader
    • International Journal of Naval Architecture and Ocean Engineering
    • /
    • v.6 no.2
    • /
    • pp.297-306
    • /
    • 2014
  • The paper presents the numerical analysis of wave run-up over rubble-mound breakwaters covered by antifer units using a technique integrating Computer-Aided Design (CAD) and Computational Fluid Dynamics (CFD) software. Direct application of Navier-Stokes equations within armour blocks, is used to provide a more reliable approach to simulate wave run-up over breakwaters. A well-tested Reynolds-averaged Navier-Stokes (RANS) Volume of Fluid (VOF) code (Flow-3D) was adopted for CFD computations. The computed results were compared with experimental data to check the validity of the model. Numerical results showed that the direct three dimensional (3D) simulation method can deliver accurate results for wave run-up over rubble mound breakwaters. The results showed that the placement pattern of antifer units had a great impact on values of wave run-up so that by changing the placement pattern from regular to double pyramid can reduce the wave run-up by approximately 30%. Analysis was done to investigate the influences of surface roughness, energy dissipation in the pores of the armour layer and reduced wave run-up due to inflow into the armour and stone layer.

Application of CFD Program for Analyzing the Hydrodynamic Characteristics of Baffled PAC Contactor (격벽식 분말활성탄 접촉조의 흐름해석을 위한 전산유체역학 프로그램의 적용)

  • Ahn, Chang-Jin;Ahn, Sang-Jin
    • Journal of Korea Water Resources Association
    • /
    • v.35 no.2
    • /
    • pp.221-229
    • /
    • 2002
  • For the efficient design of baffled Powdered activated carbon(PAC) contractor, which has been widely used in water treatment plant(WTP) against the algae-related odor problems, a CFD(computational fluid dynamics) program was applied. In order to verify the performance of FLOW-3D program, the previously reported results of tracer tests from a pilot-scale PAC contractor(working volume of 288 liters) were compared to those from FLOW 3D. The results of FLOW-3D simulation were very similar to those from tracer tests conducted with the Pilot-scale PAC contactor. On the other hand, the hydrodynamic characteristics of baffled contractor in the P-WTP were simulated by using FLOW-3D. Simulation results on the distribution of PAC particles showed that there are some stagnant parts in the back side of baffles in which PAC Particles are not present. These stagnant parts might decrease the adsorption capacity of PAC particles. When the baffles were changed to maze-type intra-basin baffling, PAC particles were evenly distributed and the amount of stagnant parts reduced. In conclusion, it is anticipated that FLOW-3D simulation could be a viab1e tool for analyzing the hydrodynamic characteristics of structures used in drinking water treatment plant.

View-Dependent Adaptive Animation of Liquids

  • Kim, Jang-Hee;Ihm, In-Sung;Cha, Deuk-Hyun
    • ETRI Journal
    • /
    • v.28 no.6
    • /
    • pp.697-708
    • /
    • 2006
  • Various adaptive mesh refinement techniques are often employed in numerical simulations for increasing spatial and temporal resolution beyond the limits imposed by available CPU time and memory space. Recently, an octree-based adaptive mesh structure was successfully used in fluid animation to place more grid cells efficiently in visually interesting regions of fluids. In an attempt to optimize the use of computational resources further in fluid animation, this paper extends this adaptive technique by modifying the mesh refinement scheme so that the camera's viewing properties are dynamically exploited during the simulation. Based on a simple adaptive mesh structure, we show that the new meshing strategy can save a substantial amount of computation time and memory space by using a view-dependent adaptive approach. The experimental results reveal that the proposed technique provides a good compromise between the computational effort and the simulation's fidelity, and may be used quite effectively in 3D animation production.

  • PDF